Expanding the Scope and Efficiency of 3D Surface Topography Analysis in Firearm Forensics

Over the past several years, advances in 3D surface metrology have made their way into the field of firearm and toolmark analysis. Accurate surface imaging coupled with high-resolution visualization tools and advanced algorithms are beginning to allow examiners to view, annotate, and share data between labs, to conduct blind verification, and to form a statistical basis for identification. This proposal aims to continue research and development within the discipline of Virtual Comparison Microscopy (VCM) for firearm forensics. First, we will extend our high-throughput cartridge case scanning platform to include bullets. Second, we will evaluate the use of a portable 3D scanning system within the crime lab and evidence response teams. The proposed work includes critical steps towards further validating the field of toolmark examination and the use of 3D scanning technology in and around the forensic lab.

The proposed work takes important next steps towards moving 3D scan acquisition and analysis technology into the crime lab. The work builds off our recent success in developing and evaluating technology for the 3D scanning and analysis of cartridge cases. In Aim 1 we will study the ability of our desktop and portable scanner systems to acquire high-resolution scans of bullet Land Engraved Areas (LEAs) and we will improve the efficiency of bullet scan acquisition by creating a tray-based high-throughput fixture. We aim to collect a high-resolution scan in under five minutes per bullet. We will also evaluate the performance of three different comparison algorithms for bullet striation profiles, a cross-correlation-based method, a feature-based method, and a segment-based method. Improving the scanning efficiency of bullets is an important next step towards the routine use of VCM in all firearms casework. In Aim 2 we will complete two deployment studies to evaluate how a fast, high-resolution, portable version of our scanner may find use within the crime lab. We believe the portable system which provides nearly instantaneous 3D surface measurements may find a useful niche given the recent emphasis on rapid turn-around time.

The work directly addresses the CFDA 16.560 solicitation's Development goal of producing novel and useful systems and methods and the Fundamental/Basic Research Goals of improving the understanding of the accuracy, reliability, and measurement validity of forensic science disciplines.

Note: This project contains a research and/or development component, as defined in applicable law. See 2 CFR 200.210(a)(14).

CA/NCF